Выражение встречается в следующем контексте:

'How are you?'
'Fine. I'm fine. Sorry, I - ' My voice sticks in my mouth.
'Are you okay?' He puts his head on one side and frowns at me.
'I-' I touch my forehead, blink hard, my hand's won't keep still. 'Sorry, I'm having a bit of a day."
Заранее спасибо